Microminiature leadless inductance element

ABSTRACT

A leadless inductance element. The element comprises a nonconductive core adapted to receive a wire winding and having first and second flanges located at the terminal portions of the core to confine the wire winding to the core. The end face of each of the flanges is flattened and an electrically conductive coating is applied to provide electrical contact with the substrate. A groove is located in each of the flanges and is adapted to receive the terminal portions of the wire winding. Finally an electrically conductive path connects the terminal portions of the wire winding with the flattened electrical contacts at the two flanges.

United States Patent [72] Inventors William L. Muclrelroy;

Marshall M. Algor, both 01 Washington, D.C.

Apr. 16, 1970 June 15, 1971 The United States of America as represented by the Secretary 01 the Army [21] Appl. No. [22] Filed [45] Patented [73] Assignee [54] MICROMINIATURE LEADLESS INDUCTANCE ELEMENT 4 Claims, 3 Drawing Figs.

[52] US. Cl. 336/192, 317/101 CC, 336/208 [51] hit. (I 1-1011 15/10 [50] Field olSenr-ch 336/192, 208, 198; 317/101 CC; 174/526; 338/322 [56] References Cited UNITED STATES PATENTS 3,271,507 9/1966 Elliott 174/526 3,312,919 4/1967 Ross 336/198X 3,393,388 7/1968 Youngm. 336/198X 3,404,214 l0/l968 Elliott. l74/52.6 3,460,246 8/1969 Hatton 336/208 X Primary Examiner-Thomas J. Kozma Attorneys-Harry M. Saragovitz, Edward J. Kelly, Herbert Berl and J. D. Edgerton ABSTRACT: A leadless inductance element. The element comprises a nonconductive core adapted to receive a wire winding and having first and second flanges located at the terminal portions of the core to confine the wire winding to the core. The end face of each of the flanges is flattened and an electrically conductive coating is applied to provide electrical contact with the substrate. A groove is located in each of the flanges and is adapted to receive the terminal portions of the wire winding. Finally an electrically conductive path connects the terminal portions of the wire winding with the flattened electrical contacts at the two flanges.

MICROMINIATURE LEADLESS INDUCTANCE ELEMENT RIGHTS OF THEGOVERNMENT The invention described herein may be manufactured, used, and licensed by or'for the United States Government for governmental purposes without the payment to me of any royalty thereon.

BACKGROUND OF THE INVENTION This invention relates to inductance elements, and more particularly to a microminiature leadless inductance element for use as a chip' on a substrate pattern.

In the manufacture and assembly of microminiature circuits for use on substrate patterns it is desirable that all the electrical elements which are mounted on the substrate be in the form of leadless inverted devices (LID), commonly known as chips. The use of such chips makes it possible to employ a numerically controlled automatic bonding tool for providing complete and automatic fabrication of these microminiature circuits. Electrical. elements such as capacitors, resistors, transistors and diodes are generally available in microminiature chip form for use on substrates; however, agreat deal of difficulty has been encountered in producing electrical inductors in microminiature chip form. In the prior art, the process of attaching and mounting inductors to microminiature substrates has usually required that the two terminal portions of wire from the inductor be separately and individually soldered to the substrate pattern. This individual treatment of inductors is inefficient and extremely time consuming.

It is therefore a primary object of this invention to provide an inductor in the form of a microminiature chip.

It is another object of this invention to provide a leadless inductance element.

Stillanother object of this invention is to provide a leadless inductance element which may be bonded to a printed circuit by using an automated bonding tool.

Yet another object of the invention is to eliminate the need for separate soldering of wires from the inductance element.

SUMMARY OF THE INVENTION Briefly in accordance with this invention, a leadless inductance element comprises a nonconductive core adapted to receive a wire winding and having first and second flanges located at the terminal portions of the core to confine the wire winding to the core The end face of each of the flanges is flattened and an electrically conductive coating is applied to provide electrical contact with the substrate. A groove is located in each of the flanges and is adapted to receive the terminal portions of the wire winding. Finally an electrically conductive path connects the terminal portions of the wire winding with the flattened electrical contacts at the two flanges.

BRIEF DESCRIPTION OF THE DRAWINGS The specific nature of the invention as well as other objects, aspects, uses and advantages thereof will clearly appear from the following description and from the accompanying drawing in which:

FIG. 1 is a perspective view of the coil bobbin for use in connection with this invention.

FIG. 2 is a perspective view illustrating the bottom portion of the inductance element in accordance with this invention.

FIG. 3 is a perspective view illustrating the top portion'of the inductance element in accordance with this invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT flangesand rooves 16 and 17 are situated between the two pro ections. he end faces of the two legs are flattened and provided with electrically conductive coatings 19 and 20 which also extend over grooves 16 and 17.

Referring now to FIG. 2, coil bobbin 10 is shown having a wire 18 wound around the core 11. Terminal portions 27 and 28 of wire 18 are stripped of insulation and are inserted into grooves 16 and 17, after which the terminal portions are secured within the grooves by means of solder or other suitable securing means. Once adequately secured withingrooves 16 and 17, the extended portions 21 and 22 of wire 18 are cut off flush with flanges 12 and 13 thereby leaving a completed leadless inductive element as shown in FIG. 3. The inductance element in FIG. 3 is then used as a chip and placed directly upon a printed circuit substrate using legs 14 and 15 as the electrical contacts with the substrate.

It will be appreciated that a novel leadless inductance element has been provided which can be automatically handled in a compatible manner along with other leadless inverted devices.

We wish it to be understood that we do not desire to be limited to the exact details of construction shown and described, for obvious modifications can be made by a person skilled in the art.

I claim as my invention:

1. A leadless inductance element comprising:

a. a nonconductive core having a wire winding thereon;

b. first and second flanges located at the terminal portions of said core to confine said wire winding to said core;

0. an electrically conductive coating on the end face of each of said flanges for providing electrical contacts with a substrate;

d. a groove located in each of said flanges for receiving the terminal portions of said wire winding; and

e. an electrically conductive path between the terminal portions of said wire winding and said electrical contacts.

2. The device of claim 1 wherein each of said flanges comprises first and second legs separated by said groove.

3. The device of claim 1 wherein the ends of said wire winding are stripped of insulation to provide electrical contact between said winding and said conductive coating.

4. The device of claim 3 further comprising means to secure the ends of said winding within said grooves. 

1. A leadless inductance element comprising: a. a nonconductive core having a wire winding thereon; b. first and second flanges located at the terminal portions of said core to confine said wire winding to said core; c. an electrically conductive coating on the end face of each of said flanges for providing electrical contacts with a substrate; d. a groove located in each of said flanges for receiving the terminal portions of said wire winding; and e. an electrically conductive path between the terminal portions of said wire winding and said electrical contacts.
 2. The device of claim 1 wherein each of said flanges comprises first and second legs separated by said groove.
 3. The device of claim 1 wherein the ends of said wire winding are stripped of insulation to provide electrical contact between said winding and said conductive coating.
 4. The device of claim 3 further comprising means to secure the ends of said winding within said grooves. 